This invention relates in general to the disposal of household waste or sewage and, in particular, to the pre-treatment of such materials before they are discharged into a municipal sewer system.
More specifically, but without restriction to the particular embodiment and/or use which is shown and described herein for purposes of illustration, this invention relates to a domestic wastewater pre-treatment unit for installation in the home to pre-treat household waste or sewage prior to discharge of these materials into a municipal sewer system. Through pre-treatment of these materials inside the home, advantage is taken of the substantially constant warm temperatures to increase the efficiency of the unit""s operational characteristics.
While various apparatus has been developed for use in the pre-treatment, or for the initial treatment, of sewage received at municipal sewage treatment plants from a municipal sewer system, such equipment does not address the problem of inadequate municipal sewer systems. As municipalities have grown, an ever increasing population generates more sewage which must be disposed of, and decreases the amount of land available to absorb melting snow and rainfall as new homes are built to house an ever growing population. These factors are major contributors to the cause of inadequate sewage treatment. Resolving this problem requires that existing sewage treatment facilities be expanded, which is a substantial cost to a municipality, or results in the overwhelming of the collection system by the input from the sewer system and storm system, referred to as combined sewer overflow, resulting in the spillage or overflow of raw and untreated sewage.
The first stage, or pre-treatment systems presently employed in municipal sewage treatment facilities, because of the volume of material received, are of a large construction. The present invention is intended for installation in a home to treat the sewage before the sewage leaves the home to be discharged into the municipal sewer system. To this end, the smaller volume of materials to be treated enables the treatment unit to utilize a more simple construction and configuration than a treatment process required to achieve the same result, but intended for use with the increased quantity of sewage and larger scale equipment required in a municipal sewage treatment plant.
Installation of the present invention in the home permits more efficient utilization of biological organisms to digest the organic material, rather than requiring the use of physical and or chemical processes to remove undesirable materials such as ammonia and phosphorus, which has been attempted by others as disclosed in J. R. Lira, U.S. Pat. No. 5,468,375 xe2x80x9cWASTEWATER PRETREATMENT TANK ASSEMBLYxe2x80x9d. In the Lira patent, unlike the present invention, a chemical process is used to strip ammonia by the addition of soda ash to raise the pH level. The chemical environment thereby created strips the ammonia. Water spills over a first weir into a stripping chamber whereat an auger dispenser periodically injects a predetermined quantity of soda ash to chemically prepare any ammonia for removal from the wastewater.
In the present invention, by utilizing biological organisms to digest organic material, activated sludge and attached growth filters remove ammonia and phosphorus. There is no need to add chemicals to the tank for treating the wastewater. The use of these biological processes, and the sequential alternation of oxygenation through the chambers of the present invention, which moves the bacteria organisms sequentially between a no oxygen environment and a high oxygen environment, enhances the removal of the phosphorus by the bacteria through incorporating the phosphorus into their cells during growth.
It is, therefore, an object of the present invention to improve systems for disposing of household wastes.
Another object of this invention is to decrease the volume of household waste material or sludge discharged into a municipal sewer system.
A further object of this invention is to decrease the volume of household waste material discharged into a municipal sewer system by the utilization of an efficient biological organism digesting process.
These and other objects are attained in accordance with the present invention wherein there is provided an enzyme-containing, in-house digester unit for receiving and treating household waste material. The in-house digester utilizes settling and biological treatment of solids and wastewater by means of biological organisms to digest the organic materials contained in the household waste, eliminating the need for the addition of chemicals or chemical treatment.